Improvements in the child support enforcement system enacted in the last ten years have greatly increased child support payments for mothers with nonmarital births. Nonetheless, the overall likelihood of receiving child support and the amount of child support received through the formal system for this group remains quite low. Findings from the Fragile Families and Child Wellbeing Study reveal that fathers with nonmarital births have substantial barriers to paying regular child support, such as low levels of education and employment and high levels of incarceration and multiple partner fertility. At the same time, it appears that most of these fathers are in good relationships with the mothers, are involved with their children, and are contributing informally in a variety of different ways. Although there is a large body of research looking at the prevalence and predictors of formal child support receipt and the effects of enforcement on this type of support, there has been scant empirical research focusing on informal cash or non-cash support. More importantly, there have been no studies looking at the effects of enforcement on these other types of father contributions to their children.

We use data from the 3-year follow-up of the Fragile Families and Child Wellbeing Survey of parents with nonmarital births to: first, describe the prevalence of formal, informal, total cash and non-cash support provided by fathers; second, to examine the bivariate relationship between formal and informal support; finally, to estimate the effect of child support enforcement on all these types of fathers' contributions to their children. We contribute to the literature in several ways: we focus on nonmarital births; we create a new comprehensive measure of enforcement which takes advantage of city and state variation in child support legislation, expenditures and implementation; and we control for a rich set of mother, father and child characteristics, many of which have not been available in prior research.

We find that mothers living in cities with strong child support enforcement are more likely to receive formal support and receive a higher amount of support; however, these increases are completely offset by a corresponding decrease in the likelihood and amount of informal support and a large decrease in the receipt of non-cash support. Therefore, mothers living in states with strong child support enforcement appear to be worse off financially than mothers living in less stringent states. These effects appear to be even more pronounced for mothers who receive welfare, the most disadvantaged group. These findings reinforce the notion that some of the provisions of the current child support enforcement system are poorly matched with the needs of low-income families. A more individualized approach to child support enforcement, where each family's circumstances are taken into consideration (whether the father is in jail, whether he is providing informally, or making regular purchases for the child), needs to be encouraged in order to improve the well-being of children in single-parent families.